In their simplest design such telescopic tracks consist of two single tracks of about the same length, the first of which is fastened onto the cabinet and the second onto the drawer. The second single track is mounted to be slidable with respect to the first single track by way of bearings, for example balls or rollers. The pulled-out length of such telescopic tracks is generally shorter than the length of the single tracks, since a part of the moving track must overlap the fixed track even in the pulled-out state to receive the moment of force arising from the weight of the drawer. In order to be able to pull a drawer completely out of the cabinet in which it belongs, double telescopic tracks are used with which for example a movable inner track is mounted in an outer track fixed in the cabinet and an outer track joined to the drawer is in turn mounted on this inner track. Thereby the pulled-out path can be doubled as compared with a single telescopic track. There have already been telescopic tracks known of the type of this class, in which the single tracks are respectively constructed as metal sections which are cold drawn or shaped from sheet metal (German Pat. No. 2,366,241).
A disadvantage of such telescopic tracks is that they are noisy in operation, since on the one hand the simple and not too precise construction of the tracks contributes to generating this kind of noise and since on the other hand, by reason of the intimate contact of all metal parts with one another, there is a barely damped transmission of the body sound to the sound-radiating surfaces of the cabinets or cases. Conversely, vibrations from the surroundings are transmitted by way of the tracks to the drawers and the articles located on them, for example technical apparatus. In particular, for the support of magnetic disk drives an extensive freedom from vibration is required for trouble-free operation. Therefore it is necessary wherever any transmission of vibration is undesirable to fasten the tracks respectively, by way of vibration-damping connecting parts, to the cabinet and/or the drawer. This on the one hand leads to an additional installation expense, especially when the places on which the rails are mounted are accessible only with difficulty. On the other hand the connecting parts generally reduce the possible width of the drawers by the installation dimensions of the connecting parts for a given size of the cabinet.
Another disadvantage is that a rigid fastening of the tracks to both the drawer and the cabinet wall necessitates a large adjusting and assembling expense because of the accuracy of dimensions to be adhered to, since any stress of the tracks against one another which would unfavorably affect the easy action properties must be avoided.